Hall-current ion source

A Hall-current ion source apparatus comprising:

• a discharge region;
• one or more apertures within said region;
• means for supplying a flow of ionizable gas to said region through said one or more apertures;
• an electron-emitting cathode at or near one end of said region;
• an anode within said region whereon said anode has an electron-collecting surface;
• a magnetic-field within said region and located between said anode and said cathode;
• discharge means to generate ions from said gas and accelerate said ions out of said region;
• characterized by said electron-collecting surface being contoured with a plurality of recesses or protrusions, wherein approximately one-third or more of the area of said electron-collecting surface cannot be reached by straight lines originating from a given point exterior of said ion source.

A Hall-current ion source apparatus comprising:

• a discharge region;
• one or more apertures proximate to said region;
• means for supplying a flow of ionizable gas to said region through said one or more apertures;
• an electron-emitting cathode at or near one end of said region;
• an anode within said region whereon said anode has an electron-collecting surface with said surface located between said apertures and said one end;
• a magnetic-field within said region and located between said anode and said cathode;
• discharge means to generate ions from said gas and accelerate said ions out of said region;
• characterized by said electron-collecting surface being contoured with a plurality of recesses or protrusions, wherein approximately one-third or more of the area of said electron-collecting surface cannot be reached by straight lines originating from a given point exterior of said ion source.

A method for making a Hall-current ion source including:

• providing a discharge region;
• providing a means for supplying a flow of ionizable gas to said region;
• providing an electron-emitting cathode at or near one end of said region;
• providing an anode within said region with said anode having an electron-collecting surface thereon;
• providing a magnetic-field within said region and located between said anode and said cathode;
• providing a discharge means to generate ions from said gas and accelerate said ions out of said region;
• and
• providing contours in said electron-collecting surface wherein said contours comprise a plurality of recesses or protrusions which increase the area of said surface by approximately one-half or more as compared to the area of said surface without said recesses or protrusions.

A method for making a Hall-current ion source including:

• providing a discharge region;
• providing a means for supplying a flow of ionizable gas to said region;
• providing an electron-emitting cathode at or near one end of said region;
• providing an anode within said region with said anode having an electron-collecting surface thereon;
• providing a magnetic-field within said region and located between said anode and said cathode;
• providing a discharge means to generate ions from said gas and accelerate said ions out of said region;
• and
• contouring said electron-collecting surface by creating a plurality of recesses in or protrusions on said surface so that approximately one-third or more of the area of said electron-collecting surface cannot be reached by straight lines originating from a given point exterior of said ion source.

A method for making a Hall-current ion source including:

• providing a discharge region;
• providing one or more apertures proximate to said discharge region;
• providing a means for supplying a flow of ionizable gas to said region through said one or more apertures;
• providing an electron-emitting cathode at or near one end of said region;
• providing an anode within said region with said anode having an electron-collecting surface thereon;
• locating said surface between said apertures and said one end;
• providing a magnetic-field within said region and located between said anode and said cathode;
• providing a discharge means to generate ions from said gas and accelerate said ions out of said region;
• and
• contouring said electron-collecting surface by creating a plurality of recesses or protrusions on said surface so that approximately one-third or more of the area of said electron-collecting surface cannot be reached by straight lines originating from a point exterior of said ion source.

A Hall-current ion source apparatus comprising:

• a discharge region;
• means for supplying a flow of ionizable gas to said region;
• an electron-emitting cathode at or near one end of said region;
• an anode having an electron-collecting surface facing said region;
• a magnetic-field within said region and located between said surface and said cathode;
• discharge means to generate ions from said gas and accelerate said ions out of said region;
• characterized by said electron-collecting surface having a plurality of recesses so as to increase the area of said surface by approximately one-half or more as compared to the area of said surface without said recesses.

A method for making a Hall-current ion source comprising the steps of:

• providing a discharge region;
• providing a means for supplying a flow of ionizable gas to said region;
• providing an electron-emitting cathode at or near one end of said region;
• providing an anode having an electron-collecting surface facing said discharge region;
• providing a magnetic-field within said region and located between said anode and said cathode;
• providing a discharge means to generate ions from said gas and accelerate said ions out of said region;
• and
• contouring said electron-collecting surface with a plurality of recesses so as to increase the area of said surface by approximately one-half or more as compared to the area of said surface without said recesses.

A Hall-current ion source comprising:

• a discharge region;
• one or more apertures within said region;
• means for supplying a flow of ionizable gas to said region through said one or more apertures;
• an electron-emitting cathode at or near one end of said region;
• an anode within said region whereon said anode has an electron-collecting surface;
• wherein said anode comprises a plurality of conducting layers separated by a respective plurality of non-conducting layers;
• wherein said non-conducting layers extend beyond said conducting layers;
• a magnetic-field within said region and located between said anode and said cathode;
• and
• discharge means to generate ions from said gas and accelerate said ions out of said region.